1. Field of the Invention
The present invention discloses an electrical control light valve apparatus, particularly to an electrical control light valve apparatus having the liquid metal.
2. Description of the Prior Art
The Thin Film Transistor-Liquid Crystal Display (TFT-LCD) is a kind of flat display technology, and is currently the main product of display in the market. Compared to other flat display technologies, including flat cathode ray tube (CRT) technology, plasma display panel (PDP) technology, back emitting technology, field emitting technology and so on, the TFT-LCD adopts relatively mature semiconductor technology. The Thin Film Transistor capable of controlling light is coated on the transparent glass substrate, and the liquid crystal material with optical rotation characteristics is employed as the display medium, in order to adjust the colour.
The conventional liquid electronic paper normally applies the “electrowetting effect” to regulate the light intensity. The electrowetting effect uses the electric field produced by the electrodes array to change the surface tension of liquid drops in order to control the motion of liquid drops in small channels. The conventional electrical light valve apparatus is shown in FIG. 1. When the voltage is not applied, the state is “close”, as illustrated in FIG. 1A. And when the voltage is applied, the state is “open”, as illustrated in FIG. 1B. The electrowetting technique mainly utilizes the immiscible property of oil and water, to superpose a hydrophobic insulation layer between the interface of the electrode and the oil drop, in order to form the light valve which can be controlled by the electric field. The hydrophobic insulation layer is used to produce the accumulation of electric charge, which causes the change of surface tension on the oil drop. The passage of light can be determined by the expansion or contraction of the oil drop, and the corresponding “close” or “open” state is formed.
However, due to the characteristic of oil, it can neither totally shield the light, nor totally reflect the light. In addition, when the light valve presents the close state, the contact angle between the oil drop and the hydrophobic insulation layer is not small enough, such that part of the light is penetrated to form light leaking phenomenon. As a result, the light valve is unable to reach high contrast of brightness and darkness, which becomes a major defect of using the liquid electronic paper.
Therefore, in order to produce more effective light valve, it is necessary to develop innovative light valve, so as to improve the power efficiency in the display and to reduce the response time and the manufacturing cost.